Apparatus and method for detecting and enabling video devices
In some embodiments, a system board may include embedded graphics capability on the system board. An expansion slot on the system board may be adapted to receive an add-in card. A first circuit on the system board may detect the presence of a graphics card in the expansion slot automatically after powering up the system board. A second circuit on the system board may determine information associated with the graphics card automatically after powering up the system board. A third circuit on the system board may be configured to utilize the information associated with the graphics card to enable or disable all or some of the embedded graphics capability automatically after powering up the system board. Other embodiments are disclosed and claimed.
The invention relates to video devices. More particularly, some embodiments of the invention relate to add-in graphics cards and on board video devices.
BACKGROUND AND RELATED ARTSome motherboards include embedded graphics. For example, graphics processing circuits and/or display driving circuits may be implemented on the motherboard. Such motherboards may further include expansion slots for add-in cards. For example, such add-in cards may include graphics cards.
BRIEF DESCRIPTION OF THE DRAWINGSVarious features of the invention will be apparent from the following description of preferred embodiments as illustrated in the accompanying drawings, in which like reference numerals generally refer to the same parts throughout the drawings. The drawings are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of the invention. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the invention may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
With reference to
For example, the graphics card may include a digital video interface (DVI) capability. For example, the third circuit 16 may be configured to enable or disable an embedded digital video interface (DVI) capability. For example, the information associated with the graphics card may include a type of the graphics card.
In some embodiments of the present invention, the first circuit 14 may be configured to utilize a pull-up and/or pull-down strap arrangement on the graphics card to detect the presence of the graphics card in the expansion slot 12. The second circuit 15 may be configured to utilize the pull-up and/or pull-down strap arrangement on the graphics card to determine the information associated with the graphics card. For example, the information associated with the graphics card may include a type of the graphics card inserted in the expansion slot.
With reference to
For example, the graphics card may include a digital video interface (DVI) capability. For example, the third circuit 26 may be configured to enable or disable an embedded digital video interface (DVI) capability. For example, the information associated with the graphics card may include a type of the graphics card.
In some embodiments of the present invention, the first circuit 24 may be configured to utilize a pull-up and/or pull-down strap arrangement on the graphics card to detect the presence of the graphics card in the expansion slot 22. The second circuit 25 may be configured to utilize the pull-up and/or pull-down strap arrangement on the graphics card to determine the information associated with the graphics card. For example, the information associated with the graphics card may include a type of the graphics card inserted in the expansion slot.
The apparatus 20 may further include a chipset 27 on the system board 21 for directing graphics signals. For example, the third circuit 26 may be configured to assert straps on the chipset 27, automatically after powering up the system board 21, to direct the graphics signals to either the embedded graphics 22 or the graphics card in accordance with the type of the graphics card inserted in the expansion slot 23.
Some embodiments of the present invention may relate to any board that implements embedded graphics (e.g. serial digital video output (SDVO)/DVI graphics) in addition to add in cards. For example, add in cards may include PCI Express (PCIe) graphics cards, Advanced Digital Display 2 (ADD2) graphics cards, and media expansion card (MEC) graphics cards.
With reference to
For example, some embodiments of the invention may utilize the unique pull-up and pull-down straps particular to a graphics card to determine the presence of the card and the type of card inserted in the slot. Once determined, the circuit may assert the proper chipset straps (i.e. if needed) and redirect the necessary signals to either the on board graphics or the graphics card (e.g. from a memory controller hub (MCH) or graphics and memory controller hub (GMCH) to either the on board DVI or the card slot).
In
For example, some embodiments of the invention may detect the type of card installed in the slot in accordance with the state of three strap pins. Table 1 gives one example of how three strap pins may be utilized to determine a type of the graphics card in a PCI slot.
After determining what type of graphics card is inserted in the slot, a chipset strap may need to be asserted to enable or disable on board graphics. Table 2 is one example of how information determined from the three strap pins may be utilized to assert a strap signal to a chipset on the system board.
With reference to
This result is latched into a flip flop. The flip flop output (see Table 2) toggles transistor circuits that assert the necessary straps to enable SDVO for the onboard DVI configuration. They also toggle the PCIe switches used to redirect the SDVO signal lines between the graphics slot and the down DVI transmitter.
The flip flop is latched by system power supply PWRGD. This is necessary because the straps are sampled by the MCH as its PWR_OK asserts. The required 100 ms (min) delay between the power supply PWRGD and the assertion of chipset PWR_OK provides ample time for the circuit to detect and assert the appropriate straps.
In conventional designs it may not be possible to implement both onboard (down) DVI and also support add in cards (or certain types of add-in cards). For example, the conventional system may support on board VGA, but all DVI solutions may have to be on add-in cards. Advantageously, some embodiments of the invention may provide the automatic capability for on board DVI while also supporting another high end add in card that the customer may decide to use.
With reference to
With reference to
- A) only PCI Express Graphics (PEG);
- B) only SDVO;
- C) always enable on-board video (DVI+VGA);
- D) when any card plugged in, then switch off onboard capability.
With reference to
A system that has an SDVO device down solution on the motherboard and a PCI Express Graphics x16 expansion slot as well may be referred to as a 3 point display system. In some embodiments SDVO video mode may be the default, but populating the x16 slot with a graphics expansion card will disable the SDVO down, enable the x16 PCI Express Graphics card, and configure the system for PCIe Graphics. For example, some implementations may also support Add2 and MEC expansion cards.
In some embodiments of the invention, strap controlling logic and PCIe switches are added to the system. For example, the straps required may be sampled by discrete logic on the on the mother board. Before the assertion of PWR_OK to the MCH, this logic may detect if an add-in card is present in the x16 slot, drive the straps accordingly, and disable the SDVO down. During the assertion of PWR_OK to the MCH, the strap values are latched in and the part boots in the correct configuration. This logic may also generate the switch select signal for the correct steering of the data to the correct location (e.g. see
In some implementations, due to the electrical characteristics of the data signals involved and because PCIe and SDVO signals may be MUXed onto the same interface on MCH, switching logic may be required to steer the data in the correct fashion.
For example, some implementations may support the following graphics modes:
In conventional systems, the strapping was static, in that pull-ups or pull-downs on the motherboard or add-in cards forced the strap values to insure the correct video mode. A problem with static strapping is that the conventional system only allowed for one video method to be supported (e.g. either an on board solution, or the x16 PCIe graphics expansion slot, but not both).
Advantageously, in a 3 point display system in accordance with some embodiments of the invention, the straps may be determined from what video devices are detected in system (e.g. by discrete logic on the motherboard). For example, in some implementations, the PCI Express HotPlug detection methodology may be utilized to detect if a PCIe graphics card is in the x16 slot. The HotPlug detection methodology requires that PRSNT1# (pin A1) on the PCIe x16 connector be tied to ground.
With reference to
For example, in some implementations, SDVO_CTRLDATA may correspond to MCH pin G17 (also routed to x16 connector pin B31) and EXP_EN may correspond to MCH pin J17 (also routed to x16 connector pin B48). Without the PCIe x16 connector populated, pin B81 will float. It will only be pulled low if an x16 card is populated through the pin Al as per HotPlug guidelines. The SDVO_CTRLDATA signal may be used as a strap on the MCH for support of ADD2 and MEC expansion cards. For example, the PRSNT2# pin (x16 connector pin B31) may be used for card detection for ADD2 and MEC expansion cards. Advantageously, VGA can be supported in any configuration.
With reference to
The strap control circuit has two basic choices: enable graphics installed on the board, or enable graphics installed via an Add-in card. As such, only the strap signals x16 Pin B81 and SDVO_CTRLDATA are necessary to determine a card presence. However, they do need to be asserted into determined states. Therefore B81 uses a weak pull up to provide a high state, and SDVO_CTRLDATA uses a weak pull down. The states may be latched into a flip-flop at the assertion of PWR_GD_SYS as follows:
In a system with an unpopulated x16 PCIe socket, the SDVO Down Enable signal is low. In this state, the SDVO down subsystem is allowed to come out of reset and be enabled via normal means. When the SDVO Down Enable signal is high (x16 slot populated), the platform reset is blocked from the SDVO down subsystem, holding it in a state of reset; allowing for the add-in card to power on normally. The strap control logic, while controlling the SDVO down subsystem, is also used as a switch select for the required PCIe switches. These switches steer the muxed signals of the SDVO/PCIe graphics interfaces to the proper place depending on configuration.
With reference to
With reference to
In particular, connecting both pin B81 and pin B7 of the X16 slot together and makes the combined signal become the B81 signal. On board, the B81 signal uses a weak pull up to provide a high state into an inverter when there is no card present in the X16 slot. The output of the inverter then provides a low state and toggles transistor circuits that assert the necessary straps to enable SDVO for the onboard DVI solution.
When any card (e.g. a graphics card) is inserted into the X16 slot, the B81 signal will be a low state, and hence toggles the inverter and transistor circuit to de-assert the necessary straps to disable the onboard DVI solution. An example state table follows:
With reference to
For example, the graphics card may include a digital video interface capability. For example, enabling or disabling all or some of the embedded graphics capability may include enabling or disabling an embedded digital video interface capability. For example, the information associated with the graphics card includes a type of the graphics card.
In some embodiments of the invention, detecting the presence of a graphics card may include utilizing a pull-up and/or pull-down strap arrangement on the graphics card to detect the presence of the graphics card in the expansion slot (e.g. at block 65). For example, determining information associated with the graphics card may include utilizing the pull-up and/or pull-down strap arrangement on the graphics card to determine the information associated with the graphics card (e.g. at block 66).
For example, the information associated with the graphics card may include a type of the graphics card inserted in the expansion slot. In some embodiments of the invention, enabling or disabling all or some of the embedded graphics capability may include asserting straps on a chipset on the system board, automatically after powering up the system board, to direct the graphics signals to either the embedded graphics or the graphics card in accordance with the type of the graphics card inserted in the expansion slot (e.g. at block 67).
With reference to
For example, the graphics card 74 may include a digital video interface capability. For example, the third circuit 78 may be configured to enable or disable an embedded digital video interface capability. For example, the information associated with the graphics card 74 includes a type of the graphics card 74.
In some embodiments of the system 70, the first circuit 76 may be configured to utilize a pull-up and/or pull-down strap arrangement on the graphics card 74 to detect the presence of the graphics card 74 in the expansion slot 73. Likewise, the second circuit 77 may be configured to utilize the pull-up and/or pull-down strap arrangement on the graphics card 74 to determine the information associated with the graphics card 74. For example, the information associated with the graphics card 74 may include a type of the graphics card 74 inserted in the expansion slot.
In some embodiments of the system 70, the third circuit 78 may be configured to assert straps on the chipset 75, automatically after powering up the system board 71, to direct the graphics signals to either the embedded graphics 72 or the expansion slot 73 in accordance with the type of the graphics card 74 inserted in the expansion slot 73. The system 70 may include additional electronic components on the system board 71 such as, for example, a processor 79 and a memory subsystem 80 (e.g. a bank of double data rate memory coupled to the system board 71).
The foregoing and other aspects of the invention are achieved individually and in combination. The invention should not be construed as requiring two or more of such aspects unless expressly required by a particular claim. Moreover, while the invention has been described in connection with what is presently considered to be the preferred examples, it is to be understood that the invention is not limited to the disclosed examples, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the invention.
Claims
1. An apparatus, comprising:
- a system board having embedded graphics capability on the system board;
- an expansion slot on the system board adapted to receive an add-in card;
- a first circuit on the system board to detect the presence of a graphics card in the expansion slot automatically after powering up the system board;
- a second circuit on the system board to determine information associated with the graphics card automatically after powering up the system board; and
- a third circuit on the system board configured to utilize the information associated with the graphics card to enable or disable all or some of the embedded graphics capability automatically after powering up the system board.
2. The apparatus of claim 1, wherein the graphics card comprises a digital video interface capability.
3. The apparatus of claim 2, wherein the third circuit is configured to enable or disable an embedded digital video interface capability.
4. The apparatus of claim 1, wherein the information associated with the graphics card includes a type of the graphics card.
5. The apparatus of claim 1, wherein the first circuit is configured to utilize a pull-up and/or pull-down strap arrangement on the graphics card to detect the presence of the graphics card in the expansion slot.
6. The apparatus of claim 5, wherein the second circuit is configured to utilize the pull-up and/or pull-down strap arrangement on the graphics card to determine the information associated with the graphics card.
7. The apparatus of claim 6, wherein the information associated with the graphics card includes a type of the graphics card inserted in the expansion slot.
8. The apparatus of claim 7, further comprising:
- a chipset on the system board for directing graphics signals,
- wherein the third circuit is configured to assert straps on the chipset, automatically after powering up the system board, to direct the graphics signals to either the embedded graphics or the graphics card in accordance with the type of the graphics card inserted in the expansion slot.
9. A method, comprising:
- powering up a system board having embedded graphics capability on the system board;
- detecting the presence of a graphics card in an expansion slot on the system board automatically after powering up the system board;
- determining information associated with the graphics card automatically after powering up the system board; and
- enabling or disabling all or some of the embedded graphics capability, automatically after powering up the system board, in accordance with the information associated with the graphics card.
10. The method of claim 9, wherein the graphics card comprises a digital video interface capability.
11. The method of claim 10, wherein enabling or disabling all or some of the embedded graphics capability includes enabling or disabling an embedded digital video interface capability.
12. The method of claim 9, wherein the information associated with the graphics card includes a type of the graphics card.
13. The method of claim 9, wherein detecting the presence of a graphics card includes utilizing a pull-up and/or pull-down strap arrangement on the graphics card to detect the presence of the graphics card in the expansion slot.
14. The method of claim 13, wherein determining information associated with the graphics card includes utilizing the pull-up and/or pull-down strap arrangement on the graphics card to determine the information associated with the graphics card.
15. The method of claim 14, wherein the information associated with the graphics card includes a type of the graphics card inserted in the expansion slot.
16. The method of claim 15, wherein enabling or disabling all or some of the embedded graphics capability includes asserting straps on a chipset on the system board, automatically after powering up the system board, to direct the graphics signals to either the embedded graphics or the graphics card in accordance with the type of the graphics card inserted in the expansion slot.
17. A system, comprising:
- a system board having embedded graphics capability on the system board;
- an expansion slot on the system board adapted to receive an add-in card;
- a chipset on the system board for directing graphics signals to either the embedded graphics or the expansion slot;
- a first circuit on the system board to detect the presence of a graphics card in the expansion slot automatically after powering up the system board;
- a second circuit on the system board to determine information associated with the graphics card automatically after powering up the system board; and
- a third circuit on the system board configured to utilize the information associated with the graphics card to enable or disable all or some of the embedded graphics capability automatically after powering up the system board.
18. The system of claim 17, wherein the graphics card comprises a digital video interface capability.
19. The system of claim 18, wherein the third circuit is configured to enable or disable an embedded digital video interface capability.
20. The system of claim 17, wherein the information associated with the graphics card includes a type of the graphics card.
21. The system of claim 17, wherein the first circuit is configured to utilize a pull-up and/or pull-down strap arrangement on the graphics card to detect the presence of the graphics card in the expansion slot.
22. The system of claim 21, wherein the second circuit is configured to utilize the pull-up and/or pull-down strap arrangement on the graphics card to determine the information associated with the graphics card.
23. The system of claim 22, wherein the information associated with the graphics card includes a type of the graphics card inserted in the expansion slot.
24. The system of claim 23, wherein the third circuit is configured to assert straps on the chipset, automatically after powering up the system board, to direct the graphics signals to either the embedded graphics or the expansion slot in accordance with the type of the graphics card inserted in the expansion slot.
25. The system of claim 17, further comprising:
- a processor on the system board.
26. The system of claim 25, further comprising:
- a double data rate memory coupled to the system board.
International Classification: G06F 3/00 (20060101);